GB209722A - Manufacture of alkyl halides - Google Patents

Abstract

The catalytic material employed in the preparation of alkyl chlorides and bromides by the interaction of an olefine in the gaseous state with hydrogen chloride or bromide comprises a compound of a metal of the fifth periodic group, particularly bismuth chloride and bromide. It is preferred to mount the catalyst on a support such as asbestos, pumice, kieselguhr or porous carbon; for example, asbestos is impregnated with a concentrated solution of bismuth chloride and heated in a current of hydrochloric acid. The Specification as open to inspection under Sect. 91 (3) (a) describes also the use of the oxides, hydroxides, halides and oxyhalides of bismuth, antimony, and vanadium, bismuth nitrate and the chlorides of niobium and tantalum as catalytic materials. This subject-matter does not appear in the Specification as accepted.ALSO:Alkyl chlorides and bromides are prepared by passing an olefine in the gaseous state in admixture with hydrogen chloride or bromide at a temperature below 250 DEG C. over a catalytic material comprising compounds of metals of the fifth gaseous hydrochloric or hydrobromic acid over bismuth chloride or bromide, whilst isopropyl chloride or bromide results if the ethylene be replaced by propylene. Furthermore, gas mixtures containing olefines may be used, for instance, lighting gas, coke-oven gas, oil gas or gas mixtures obtained by cracking petroleum products. In these cases, the reaction gases are first washed with water to remove excess of hydrogen halide and the alkyl halide then separated by cooling, by washing with a solvent or by absorption on activated charcoal and the like. The Specification as open to inspection under Sect. 91 (3) (a) describes also the use of the oxides, hydroxides, halides and oxyhalides of bismuth, antimony and vanadium, bismuth, nitrate and the chlorides of niobium and tantalum as catalytic materials. This subject-matter does not appear in the Specification as accepted.